A disulfide bond is a covalent bond between two sulfur atoms (–S–S–) formed by the coupling of two thiol (–SH) groups. Cysteine, one of 20 protein amino acids, has a –SH group in its side chain, and can easily be dimereized to cystine in aqueous solution by forming a disulfide bond.
Where can disulfide bonds form?
Disulfide bond formation generally occurs in the endoplasmic reticulum by oxidation. Therefore disulfide bonds are mostly found in extracellular, secreted and periplasmic proteins, although they can also be formed in cytoplasmic proteins under conditions of oxidative stress.
Do disulfide bonds form in oxidizing environment?
The formation of disulfide bonds occurs during the folding of proteins in the endoplasmic reticulum of eukaryotes and the periplasmic space of prokaryotes. … For a disulfide bond to form, the redox environment must be oxidizing. Eukaryotic ER is more oxidizing than the surrounding cytosol.